ATMEL AT86RF211DAI

Features
•
•
•
•
•
•
•
•
Multiband Transceiver: 400 MHz to 950 MHz
Monochip RF Solution: Transmitter-Receiver-Synthesizer
Integrated PLL and VCO: No External Coil
Very Resistant to Interferers by Design
Digital Channel Selection
200 Hz Steps
Data Rates up to 64 kbps with Data Clock and no Manchester Encoding Required
High Output Power Allowing Very Low Cost Printed Antennas:
– +10 dBm in the 915 MHz Frequency Band
– +12 dBm in the 868 MHz Frequency Band
– +14 dBm in the 433 MHz Frequency Band
• FSK Modulation: Integrated Modulator and Demodulator
• Power Savings:
– Stand Alone "Sleep" Mode and "Wake-up" Procedures
– 8 Selectable Digital Levels for Output Power
– High Data Rate and Fast Settling Time of the PLL
– Oscillator Running Mode "Ready to Start"
– Analog FSK Discriminator Allowing Measurement and Correction of Frequency
Drifts
• 100% Digital Interface through R/W Registers Including:
– Digital RSSI
– VCC Readout
FSK
Transceiver for
ISM Radio
Applications
AT86RF211
(aka: TRX01)
Description
The AT86RF211 (aka: TRX01) is a single chip transceiver dedicated to low power
wireless applications, optimized for licence-free ISM band operations from 400 MHz to
950 MHz. Its flexibility and unique level of integration make it a natural choice for any
system related to telemetry, remote controls, alarms, radio modems, Automatic Meter
Reading, hand held terminals, high-tech toys, etc. The AT86RF211 makes bidirectional communications affordable for applications such as secured transmissions with
hand-shake procedures, new features and services, etc. The AT86RF211 can easily
be configured to provide the optimal solution for the user’s application: choice of external filters vs. technical requirements (bandwidth, selectivity, immunity, range, etc), and
software protocol (single channel, multiple channel, FHSS). The AT86RF211 is also
well adapted to battery operated systems, as it can be powered with only 2.4V. It also
offers a “Wake Up” receiver feature to save power by alerting the associated microcontroller only when a valid inquiry is detected.
Rev. 1942C–WIRE–06/02
1
General Overview
General Overview of
Functioning
The AT86RF211 is a microcontroller RF peripheral: all the user has to do is to write/read
registers to setup the chip (i.e. frequency selection) or have information about parameters such as RSSI level, Vbattery, PLL lock state. All these operations are carried out via
a three-wire serial interface.
Normal Mode
The chip is set-up by the microcontroller: frequency and mode (Rx or Tx). Then it acts
like a "pipe": any data entering DATAMSG is immediately radiated (Tx) or any wanted
signal collected by the aerial is demodulated, transferred to the microcontroller by the
same pin DATAMSG (Rx) as reshaped bits. No data is stored or processed into the
chip. See Figure 1.
Note:
Wake-up Mode
In Rx mode, a clock recovery DATACLK is available on the digital interface to provide the
microcontroller with a synchronization signal.
The chip is set up in a special Rx mode called sleep mode. The chip wakes up periodically thanks to its internal timer (stand alone procedure, the microcontroller is in powerdown mode), waiting for an expected message previously defined. If no correct
sequence is received, the periodic scan continues.
If a correct message is detected, its data field is stored into the AT86RF211 (up to 32
bits) and an interrupt is generated on the WAKEUP pin.
See Figure 2 and Figure 3.
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AT86RF211
Figure 1. Reception and Transmit Mode
F = Frequency of
transmitted signal
AT86RF211 (TRX01)
SLE, SCK, SDATA
(for set-up)
Transmit mode
3
Companion Microcontroller
DATAMSG
AT86RF211 acts like a "pipe"
(data is transmitted with NO
processing): automatic data
to frequency conversion.
- DATAMSG = 0: F = F0
- DATAMSG = 1: F = F1
F = Frequency of
received signal
AT86RF211 (TRX01)
SLE, SCK, SDATA
(for set-up)
Receive mode
3
AT86RF211 also acts like a "pipe":
data (collected by the antenna)
is available on pin DATAMSG:
Companion Microcontroller
DATACLK
DATAMSG
DATAMSG
DATACLK
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Figure 2. Wake-up Overview
Header + Address
Data field
Step 2: The chip wakes-up periodically,
waiting for an expected message
(stand-alone operation)
AT86RF211 (TRX01)
Step 1: The chip is set up in sleep mode
using the 3-wire interface (SLE, SCK,
SDATA), then Microcontroller goes to sleep,
waiting for an interrupt on WAKEUP pin
Data stored
Wake-up mode
3
Companion Microcontroller
WAKEUP pin
Step 3: If a correct header is received (mandatory)
and address matches (if any), the data field
is then stored into AT86RF211 and WAKEUP pin is
activated (to wake-up the Microcontroller).
The Microcontroller will then read the data into one
of its registers, and begin a relevant procedure.
Note: Data field is optional: the chip can be simply
woken-up with no dedicated data.
Figure 3. Periodical Scan
Power
Consumption
Reception mode
Short reception window
Oscillator settling
Sleep mode
Wake Up period
Timing
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AT86RF211
Block Diagram
Figure 4. AT86RF211 Block Diagram
Optional
RF
FILTER
AERIAL
MATCHING
CIRCUIT
IF2
FILTER
455 kHz
IF1
FILTER
These are the only blocks that depend
on the selected ISM band (433, 868
or 915 MHz): dual band applications
can be done by only switching them.
Synthesizer, loop filter, IF filter(s),
power supply decoupling are identical.
10.7 MHz
or
21.4 MHz
TX/RX
LNA
IF1
AMP
MIXER1
IF2
AMP
MIXER2
FM DISCRIMINATOR
Rx
GAIN MIN/MAX
RSSI LEVEL
TX
OPTIONAL
FILTER
BANDWIDTH CTRL
SYNTHESIZER
PA
DATA SLICER
FREQUENCY
CTRL
RPOWER
CONTROL LOGIC
PWR
CTRL
WAKE-UP
OSC
10.245 MHz
or
20.945 MHz
DATA DATA SLE
SDATA
SCK
MSG CLK
WAKE-UP
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Pin Description
Table 1. Pinout
Pin
Name
Comments
Pin
Name
Comments
1
RPOWER
Full scale output power resistor
25
SKFILT
Threshold for data slicer
2
TXGND1
GND
26
DSIN
Data slicer input
3
RF
RF input/output
27
DISCOUT
Discriminator output
4
TXGND2
GND
28
IF2VCC
VCC
5
TXGND3
GND
29
IF2GND
GND
6
TXGND4
GND
30
IF2IN
IF2 amplifier input
7
TXVCC
VCC
31
IF2DEC
2.2 nF to ground
8
TXGND5
GND
32
DISCFILT
Discriminator bypass
9
DIGND
GND
33
IF2OUT
IF2 mixer output
10
DIVCC
VCC
34
IF1DEC
4.7 nF to ground
11
DATAMSG
Input/output digital message
35
IF1IN
IF1 amplifier input
12
SLE
Serial interface enable
36
IF1OUT
IF1 mixer output
13
SCK
Serial interface clock
37
AGND
GND
14
SDATA
Serial interface data
38
AVCC
VCC
15
WAKEUP
Wake-up output
39
CVCC2
VCC
16
DATACLK
Data clock recovery
40
CGND2
GND
17
–
Test pin: do not connect
41
FILT1
Synthesizer output
18
EVCC1
VCC
42
VCOIN
Synthesizer input (VCO)
19
EGND1
GND
43
EVCC2
VCC
20
–
Test pin: do not connect
44
EGND2
GND
21
CGND1
GND
45
RXIN
LNA input from SAW filter
22
CVCC1
VCC
46
RXVCC
VCC
23
XTAL1
Crystal input
47
RXGND
GND
24
XTAL2
Crystal output
48
SWOUT
Switch output
Notes:
6
1. All VCC pins must be connected in each functional mode (Tx, Rx, wake-up, PDN)
2. To be connected:
Rx mode only, all but: 1, 3, 17, 20, 48
Tx mode only, all but: 15 to 17, 20, 25 to 27, 30 to 36, 45, 48
3. Pin 20 must remain unconnected or connected to ground
AT86RF211
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AT86RF211
Detailed Description
Frequency Synthesis
Crystal Reference Oscillator
The reference clock is based on a classical Colpitts architecture with three external
capacitors.
An XTAL with load capacitor in the range of 10 pF - 20 pF is recommended. The bias
circuitry of the oscillator is optimized to produce a low drive level for the XTAL. This
reduces XTAL aging. Any standard, parallel mode 10.245 MHz or 20.945 MHz crystal
can be used.
Note:
The PLL is activated only when the oscillator is stabilized.
Figure 5. Crystal Oscillator Inputs
XTAL1
XTAL2
Figure 6. Typical Networks
XTAL2
XTAL1
XTAL2
XTAL1
C1 = 82 pF
C1 = 68 pF
CL = 16 pF (1)
CL = 20 pF
(1)
C2 = 56 pF
15 pF
Notes:
6.5/30 pF
(2)
C2 = 68 pF
33 pF
6.5/30 pF
(2)
1. Various load capacitance (CL) crystals can be used. In case CL differs of 16 pF or 20 pF, the surrounding network (C1, C2)
must be re-calculated.
2. Thanks to the fine steps of the synthesizer (200 Hz), the trimmer capacitor can be replaced by a software adjustment.
Synthesizer
A high-speed, high-resolution multi-loop synthesizer is integrated. The synthesizer can
operate within two frequency bands: 400 MHz to 480 MHz and 800 MHz to 950 MHz. All
channels in these two bands can be selected through software programming (registers
F0 to F3). All circuitry is on-chip with the exception of the PLL loop filter. The phase
comparison is made thanks to a charge pump topology. Typical charge pump current is
225 µA.
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Figure 7. Synthesizer Loop Filter Schematic
VCO
PFD
&
CHP
Fref
FILT1
Note:
8
VCOIN
The PLL loop filter can be designed to optimize the phase noise around the carrier.
Three configurations can be suggested, regarding the application and channel spacing:
- Narrow band: (14.7 kΩ + 2.2 nF) // 220 pF
- Typical: (3.3 kΩ + 5.6 nF) // 560 pF
- High datarates: (10 kΩ + 1 nF) // 100 pF
AT86RF211
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AT86RF211
Receiver Description
Figure 8. Typical Expected Currents in Rx Mode
Supply Current - Rx Mode
32.00
Isupply (mA)
868 or
915 MHz
30.00
433 MHz
28.00
26.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
Vsupply (V)
Detailed Current - Rx Mode
EVCC2
Supply Currents (mA)
10.00
8.00
6.00
EVCC1
RXVCC
4.00
CVCC2
CVCC1
AVCC
2.00
0.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
DIVCC
IF2VCC
TXVCC
4.25
Vsupply (V)
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Overview and Choice of
Intermediate Frequencies
For selectivity and flexibility purpose, a classical and robust 2 IF superheterodyne architecture has been selected for the AT86RF211. In order to minimize the external
components cost, the most popular IF values have been chosen. The impedances of the
input/output of the mixing stages have been internally matched to the most usual
ceramic filter impedances.
Two typical IF values are suggested:
•
10.7 MHz is the most popular option.
•
21.4 MHz: the image frequency is far enough from the carrier frequency to enable
the use of a front-end ceramic filter instead of a SAW filter. It is also noticeable that
21.4 MHz quartz filters usually have more abrupt slopes than 10.7 MHz ceramic
filters.
Rx - Tx Switch
A SPST switch is integrated. In the transmission mode, it protects the LNA input from
the large voltage swings of the PA output (up to several volts peak-to-peak), which is
switched to a high impedance state. It is automatically turned ON or OFF by the RX/TX
control bit. The insertion loss is about 2 dB and the reverse isolation about 30 dB in a
300Ω environment.
Image Rejection and RF Filter
The immunity of the AT86RF211 can be improved with an external band-pass filter.
For example, when using a SAW Filter, this device must be matched with the LNA input
and the switch output. The following scheme gives the typical implementation for an
868 MHz application with a 50Ω/50Ω SAW filter.
Figure 9. Typical 50Ω SAW Filter Implementation in the 868 MHz Band
These inductors can be printed
SWOUT (pin 48)
2.2 nH
12 nH
SAW
SPST Switch
50Ω
RXIN
(pin 45)
See Table 2 for precise matching information.
The SAW filter can be replaced by a TEM ceramic, helicoidal or a ceramic coax λ/4 resonator designed as a narrow band-pass filter. For instance, with an IF selected at
10.7 MHz, a -3 dB bandwidth of 5 MHz, with an insertion loss of 1 dB and an image
rejection of 12 dB can be achieved with the following:
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AT86RF211
Figure 10. TEM Filter
1 pF
1 pF
λ /4
Zc = 7Ω
TEM
l = 0.75
(19 mm)
Such a filter also provides an out-of-band interference rejection greater than 20dB,
40 MHz away from 433 MHz.
First LNA/Mixer
The main characteristics of the LNA/Mixer are typically:
•
Voltage gain: 17 dB for the LNA/Mixer; 11 dB if gain min. is selected
•
Bandwidth: 1.2 GHz
•
Noise figure of LNA alone: 3 dB at 900 MHz, best matching
•
Noise figure of LNA + mixer:
8 dB at 900 MHz, with maximum gain and best matching
12 dB at 900 MHz, with minimum gain and best matching
•
1 dB compression point: -20 dBm at the input of LNA
•
Matching:
Table 2. Matching Information
Notes:
Frequency Band
RXIN(1)
SWOUT(2)
433 MHz
35 + j 170Ω
24 - j 43Ω
868 MHz
37 + j 85Ω
50 - j 42Ω
915 MHz
30 + j 85Ω
50 - j 42Ω
1. RXIN: impedance to be seen by LNA input for NF optimization purpose
2. SWOUT: output impedance of the RF switch
The gain is programmable through bit 25 of CTRL1 register (6dB attenuation when min
gain is selected). The choice for the matching between the SWITCH and the LNA
depends mainly on the chosen SAW filter. Usually in/out impedance of SAW filters is
50Ω, but other ones can be implemented and the matching network recalculated thanks
to the previous impedance table.
The LNA is directly coupled to the first mixer. Input and output of the LNA/Mixer must be
connected through a capacitive link because of their internal DC coupling. A SAW or
ceramic filter provides such a link.
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Figure 11. Schematic Input of the LNA
RXIN
Figure 12. Schematic Output of the Mixer
IF1OUT
The first mixer translates the input RF signal down to 10.7 MHz or 21.4 MHz as chosen
by the user. The local oscillator is provided by the same synthesizer which will generate
a local frequency 10.7 MHz or 21.4 MHz away from the Tx carrier frequency.
The output impedance of the mixer is 330Ω with a 20% accuracy, so that low cost, standard 10.7 MHz ceramic filters can be directly driven. Other IFs may be chosen thanks to
the high bandwidth (50 MHz) of the mixer.
IF1 filtering
A popular ceramic filter is used to reject the second image frequency and provide a first
level of filtering.
The IF1 filter can however be removed; it leads to a sensitivity reduction of about 3 dB
(the substitution coupling capacitor should be > 100 pF).
IF1 Gain and Second Mixer
12
The input impedance of the IF1 amplifier is naturally 330Ω to match the input filter. The
voltage gain, i.e. gain at 10.7 MHz or 21.4 MHz added to the conversion gain at 455 kHz
is typically 14 dB when loaded by 1700Ω. The second mixer operates at a fixed LO frequency of 10.245 MHz or 20.945 MHz. Its output impedance is 1700Ω in parallel with 20
pF.
AT86RF211
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AT86RF211
Figure 13. IF1 Filtering
IF1 Filter
IF1OUT
(pin 36)
IF1IN
(pin 35)
"or"
330 Ω
330 Ω
C > 100 pF
Figure 14. Schematic Input of IF1 Amplifier
IF1IN
330Ω
20 k Ω
IF1DEC
Figure 15. Schematic Output of the Second Mixer
1600 Ω
IF2 Filtering and Gain
IF2OUT
IF2 filtering achieves a narrow channel selection. In case it is not used, it should be
replaced by a > 1 nF coupling capacitor, thus the IF1 filter is the only part achieving the
channel selection. Available commercial filters with a 35 kHz BW allow data rates up to
19.6 kbps if crystal temperature drifts are very low.
For faster communications and/or wider channelization, this ceramic filter can be
replaced by an LC band-pass filter as proposed hereafter.
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Figure 16. LC Band-pass Filter
10 nF
10 nF
F1
F2
Filter
gain
global response
Frequency
~ F1
~ F2
40 kHz or higher
IF2 Amplifier Chain
•
10 nF capacitors cut DC response forward and backward.
•
The first network has the low cut-off frequency.
•
The second network has the high cut-off frequency.
The input impedance of the IF2 amplifier is 1700Ω. This value enables the use of popular filters with impedance between 1500Ω and 2000Ω. It is directly connected to the FSK
demodulator. The bandwidth is internally limited to 1 MHz to minimize the noise before
the discriminator. It acts like a band pass filter centered at 455 kHz with capacitive coupling between stages of amplifier and mixer. Total voltage gain is typically 86 dB.
Thanks to the capacitive coupling, no slow DC feedback loop is needed enabling a fast
turn on time. IF2DEC has to be decoupled with at least 2.2 nF.
Figure 17. Input of the IF2 Amplifier Schematic
IF2IN
1900 Ω
IF2DEC
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AT86RF211
RSSI Output
The RSSI value can be read as a 6 bits word in the STATUS register. Its value is linear
in dB as plotted below:
Figure 18. Typical RSSI output (board implementation, T = 25°C, VCC = 3V)
RSSI Output
70
60
RSSI Code
50
Dispersion: +/-5dB
40
30
20
Dynam ic Range: 50dB
10
0
-110
-100
-90
-80
-70
-60
-50
-40
-30
Power Level at Antenna Input Port (dBm)
Note:
Should the RSSI be required for accurate measurement purpose (precision better than 5 dB), then it is possible to measure one
value with a calibrated RF source and store it into the microcontroller, during the production testing.
The RSSI dynamic range is 50 dB from -95 dBm to -45 dBm RF input signal power, over
temperature and power supply ranges. The RSSI LSB’s value weighs about 1.3 dB in
the linear area. The RSSI value is measured from the IF2 chain.
The RSSI is periodically measured thanks to a successive approximation ADC with a
12 µs clock. Thereafter, the time needed to complete the right code depends on the
power step: a 10 dB step on the aerial leads to a 10/1.3 = 8 clock cycles, i.e. 96 µs (full
range from code 0 to 63 = 756 µs). Its value can be compared with a user predefined
value (TRSSI), so that the demodulated data is enabled only if the RSSI value is above
this threshold. Some hysteresis effect may be added (see CTRL1 register’s content).
The AT86RF211 also has the possibility to measure another voltage. The ADC measuring the RSSI can be turned into voltage or discriminator output DC level measurement.
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Figure 19. ADC Converter Input Selection
STATUS register
MRSSI
RSSI
Vcc supply
M
U
X
DISCOUT
(MOFFSET)
M
U
Voltage X
M
U
X
ADC
MVCC
CTRL1[1]
CTRL1[24]
Note:
For voltage measurement, the LSB weighs 85 mV and the reference voltage is 1.25V.
The ADC measuring the RSSI can be turned into voltage or discriminator output DC
level measurement.
FSK Demodulator
Its structure is based on an oscillator:
Figure 20. Schematic of the FSK demodulator
oscillator
Fin
A
RBW
B
C
FD
The oscillator’s natural frequency is FD and it actually oscillates at the Fin frequency.
The signal at the output of the oscillator (point A) is proportional to the frequency difference between Fin and FD. The XOR function translates the difference into a pulse duty
cycle (point B).Thereafter by low-pass filtering of the signal is obtained a mean voltage
of the signal (point C).
The architecture of this demodulation is thereby analog and allows the transmission of
continuous data stream of the same value as the output voltage is proportional to the
input frequency. Thus it is not mandatory to use Manchester encoding and the first bit is
correctly demodulated.
The oscillator feedback resistor controls the center frequency FD. It is adjusted according to the output of a dummy FSK demodulator driven by a 455 kHz internal reference
frequency which is a division of the reference crystal. The discrete components connected to pin 32 DISCFILT are the loop filter of the PLL stabilizing the 455 kHz signal.
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AT86RF211
The input RBW resistor controls the discriminator bandwidth. This bandwidth is selected
by CTRL1[6]. The default value is "standard discriminator BW". The slope of the discriminator increases by 5 mV/kHz/V with VCC and is 14 mV at 2.4V.
Example:
VCC = 3V implies +17 mV/kHz sensitivity for the demodulator
VCC = 3.6V implies +20 mV/kHz sensitivity for the demodulator
Data Slicer
The analog signals at the output of the discriminator (DISCOUT, pin 27) are converted
into CMOS level data by a high resolution comparator called a Data Slicer.
The Data Slicer has a reference for its comparator which can be chosen thanks to
CTRL1[4]. The reference sets the comparison level of the comparator. One option is to
extract the average value of the demodulated signal on the SKFILT pin (25), this is the
external mode. The other option is to set an absolute value for this reference (internal
mode).
•
External mode:
The external mode uses the average value of the demodulated signal as the comparison level for the comparator. Thus there must be enough transitions in the message to
ensure that the average value remains between the "0" level and the "1" level. Manchester encoding can be used in this mode as well as DC-free encoding schemes. The
choice for SKFILT capacitor is a trade-off between the maximum duration of a constant
bit (whatever "0" or "1") and the max allowed settling time to charge this capacitor after
powering up.
Note:
•
The SKFILT pin is in high impedance state during the "sleep" period of the Wake Up
mode, so that the level is kept constant and there is no need to charge again this tank.
Internal mode:
The internal mode uses the output of a DAC as the comparison level. Once this threshold has been correctly set, an "absolute" data slicing of the demodulated signal is
possible: no need for DC-free modulation scheme (it is possible to send a "0" or "1"
infinitely).
Figure 21. Schematic of the Data Slicer
DISCOUT
+
-
DATAMSG
+
+
-
DSIN
-
4 bits
Σ
+
+
Choice of internal or
external reference for
the data slicer
Vdd/2
100 kΩ
SKFILT
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To operate this way, the user must make sure that the "0" and "1" level at the output of
the discriminator are "on both sides" of the comparison level in order for the decision to
be made properly.
Figure 22. How to Set Up the Data Slicing Parameters
DISCOUT:
demodulated
data
Not OK
Comparator threshold
OK
Time
To set the discriminator and the Data Slicer accordingly:
–
It is possible to measure the output DC level of the discriminator DISCOUT
(thanks to the A/D embedded converter)
–
DTR[1:0] make it possible to shift (up or down) the DC level at the output of
the discriminator :
- DTR[1] = 1: +180 mV + 77x (VCC - 2.4V)
- DTR[0] = 1: -180 mV - 77x (VCC - 2.4V)
–
DTR[5:2] make it possible to tune the comparison threshold around VCC/2.
16 levels are possible, with a LSB = 15 mV per Volt of supply voltage. VCC/2
corresponds to DTR[5:2] = 0111, and the RESET value is 1000.
These procedures can be made automatically by software. Please refer to the application note.
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AT86RF211
Transmitter Description
Figure 23. Typical Expected Currents in Tx Mode
Supply Current - Tx Mode
65.00
915MHz
868MHz
60.00
55.00
Isupply (mA)
50.00
433MHz
45.00
40.00
35.00
30.00
25.00
20.00
15.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
Vsupply (V)
Detailed Current - Tx Mode
30.00
PA
Supply Currents (mA)
25.00
20.00
TXVCC
15.00
EVCC2
10.00
EVCC1
5.00
CVCC2
CVCC1
RXVCC
DIVCC
0.00
2.25
2.50
2.75
3.00
3.25
3.50
3.75
4.00
4.25
Vsupply (V)
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Power Amplification
The Power Amplifier has been built to deliver more than +10 dBm, i.e. 10 mW in the
three popular frequency bands. This power level is intended to be measured on the
aerial port with a correct output matching network. Note that a correct calculation of the
matching network guarantees an optimal power efficiency.
Naturally, the greater the PA output voltage swing, the better the power efficiency. As
the PA output is supplied through an inductor, a swing of 2 x VDD is possible. In practice,
due to saturation effects, the voltage swing is limited to approximately (2 x VDD) - 1V.
With a power supply voltage of 3V, the PA output voltage is 5V peak-to-peak, or
1.77 VEFF.
Figure 24. Output of the Power Amplifier
The PA must be correctly matched to deliver the best efficiency in terms of output power
and current consumption. Here is an example of the typical recommended output network in the 868 MHz band:
Figure 25. Output Matching at 868 MHz
Power supply
filtering
Vcc
12 nH
Supply
inductor
aerial
RF
PA output
1.5 nH
~ 50Ω matched filtering
50Ω
Note:
The filter is designed to meet relevant regulations. Please refer to application note for details.
A benefit of this network is to filter the output signal harmonic levels; hence it can be
designed to meet a particular regulation.
It is mandatory to implement low impedance grounding techniques. Excessive inductor
values to ground will not only limit the PA output voltage swing, but may also trigger RF
instability. Board design is vital to avoid parasitic loss when high output power is needed
(direct short connection to a single low impedance ground plane).
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AT86RF211
An automatic level control loop (ALC) is integrated, in order to minimize the sensitivity of
the PA to the temperature, process and power supply variations. For instance, at +85°C,
the output power is about 2 dB less than at 25°C. At -40°C, the output power is higher
than at 25°C. The ALC is controlled by a current which is generated in the following way:
Figure 26. ALC of the Power Amplifier
iref =
(v)
U
1.25 V
V
RPOWER
I
IOUT
To ALC
3 bits
DAC
RPOWER
digital
≅ 18 k Ω
power control
Figure 27. Typical Output Power of the PA for T = 25°C and VCC = 3V
Output Power
14
433MHz
12
868MHz
Pout (dBm)
10
915MHz
8
6
4
2
0
-2
26
31
36
41
46
51
56
61
Isupply (mA)
Hardware Control
The max output power is determined by RPOWER and the maximum output power is
obtained with RPOWER = 10 kΩ.
18 kΩ is the nominal value for a +10 dBm output in the 868 MHz frequency band.
Decreasing this value to 10 kΩ will lead to +14 dBm at 433 MHz, +12 dBm at 868 MHz,
+10 dBm at 915 MHz (typical values for conducted output power).
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1942C–WIRE–06/02
Figure 28. RPOWER Input Schematic
100 Ω
Note:
Software Control
RPOWER
Keeping the PA output matched guarantees maximum power efficiency.
The power can then be adjusted, from the value set by RPOWER down to a maximum of
12 dB below, by programming the bits 6 to 8 of the CTRL1 register. So, 8 levels are digitally selectable with a variation of the output power. The minimum regulated output
power is set to -10 dBm.
Table 3. Software Control of the Power Level
TXLVL (CTRL1)
Pout at 433 MHz
(dBm)
Pout at 868 MHz
(dBm)
Pout at 915 MHz
(dBm)
000
0
-2
-3
001
4
0
0
010
6
3
2
011
8
5
4
100
10
7
5
101
11
8
7
110
12
9
8
111
13
10
9
Note:
Unless otherwise specified, typical data given for RPOWER = 18 kΩ, T = 25°C, VCC = 3 V
Control Logic
Serial Data Interface
The application microcontroller can control and monitor the AT86RF211 through a synchronous, bidirectional, serial interface made of 3 wires:
•
SLE: enable input
•
SCK: clock input
•
SDATA: data in/out
When SLE = ‘1’, the interface is inhibited, i.e. the SCK and SDATA (in) values are not
propagated into the IC, reducing the power consumption and preventing any risk of parasitic write or read cycle.
A “read” or “write” cycle starts when SLE is set to ‘0’ and stops when SLE is set to ‘1’.
Only one operation can be performed in one access cycle: only one register can be
either read or written.
22
AT86RF211
1942C–WIRE–06/02
AT86RF211
• Register Interface Format
A message is made of 3 fields:
–
address A[3:0]: 4 bits (MSB first)
–
R/W: read/write selection
–
data D[31:0]: up to 32 bits (MSB first)
ADDRESS
A[3]
A[2]
R/W
A[1]
A[0]
DATA up to 32 bits (variable length)
R/W
MSB
D[nbit-1:0]
LSB
Variable register length and partial read or write cycles are supported.
In case of partial read or write cycles, the first data (in or out) is always the MSB of the
register.
• WRITE Mode (R/W = 1)
The address, R/W and data bits are clocked on the rising edge of SCK.
If the number of data bits is lower than the register capacity, the LSB bits keep their
former value allowing safe partial write. If the number of data bits is greater than the register capacity, the extra bits are ignored.
The data is actually written into the register on the rising edge of SLE when the data
length is less or equal to the register length.
When trying to write more data than the register length, data field is written on the first
extra rising clock edge regarding register length.
Figure 29. Write Chronogram: Complete Write Cycle in a 10 bits Register
SLE
SCK
SDATA
A[3]
A[2]
A[1]
A[0]
R/W
D[9]
D[8]
D[7]
D[6]
D[5]
D[4]
D[3]
D[2]
D[1]
D[0]
The complete register of 10 bits is updated on a rising edge of SLE.
Figure 30. Write Chronogram: Partial Write Cycle, Writing 2 bits
SLE
SCK
SDATA
A[3]
A[2]
A[1]
A[0]
R/W
D[31] D[30]
23
1942C–WIRE–06/02
Only the 2 MSBs are updated on the rising edge of SLE; other register bits are
unchanged.
• READ Mode (R/W = 0)
The address and R/W bits are clocked on the rising edge of SCK.
The data bits are changed on the falling edge of SCK. The MSB of the register is the first
bit read.
SDATA I/O pin is switched from input to output on the edge following the "1" clocking the
R/W bit.
It is possible to stop reading a register (SLE back to “1”) at any time.
If an attempt to read more bits than the register capacity is detected, SDATA is clamped
to “0”.
If the address of a register is not valid, SDATA is set to “1” during the first 32 SCK periods, then to “0” during all the extra periods.
SDATA is switched back to the input state when SLE is back to “1”.
Figure 31. Read Chronogram: Complete Read Cycle from a 10 bits Register
SLE
SCK
SDATA
A[3]
A[2 ]
SDATA
direction
A[1]
A[0]
R/W
D[9 ]
D[8]
D[7]
INPUT
D[6]
D[5]
D[4]
D[3]
D[2]
OUTPUT
D[1]
D[0]
INPUT
Figure 32. Read chronogram: Partial Read Cycle, Reading 2 bits
SLE
SCK
SDATA
SDATA
mode
24
A[3] A[2] A[1] A[0] R/W D[31] D[30]
INPUT
OUTPUT
INPUT
AT86RF211
1942C–WIRE–06/02
AT86RF211
Figure 33. Chronogram with Timing
tdle
tdle
SLE
T
tw
tw
SCK
tsd
SDATA
A[3]
A[2]
SDATA
direction
Note:
thd
A[1]
tpzon
A[0] R/W
D[9 ]
tpd
tpzd
D[8] D[7] D[6] D[5] D[4] D[3] D[2] D[1] D[0]
INPUT
OUTPUT
INPUT
For the timing specification, please refer to the timing table “Digital CMOS DC Characteristics” on page 42.
Registers
Table 4. Registers Overview
Name
Address A[3:0]
Nbits
Read-Write
Comments
F0
(0000)2
32
R-W
F0 Frequency Code
F1
(0001)2
32
R-W
F1 Frequency Code
F2
(0010)2
32
R-W
F2 Frequency Code
F3
(0011)2
32
R-W
F3 Frequency Code
CTRL1
(0100)2
32
R-W
Main Control Register
STAT
(0101)2
31
R
DTR
(0110)2
6
R-W
Data Slicer Reference/Discriminator offset adjusting
WUC
(0111)2
32
R-W
Wake-up Control Register
WUR
(1000)2
18
R-W
Wake-up Data Rate Register
WUA
(1001)2
25
R-W
Wake-up Address Register
WUD
(1010)2
32
R
Wake-up Data Register
RESET
(1011)2
1
W
Reset
-
(1100)2
Reserved
-
(1101)2
Reserved
-
(1110)2
Reserved
CTRL2
(1111)2
Note:
32
R-W
Status Register
Control Register (Lock Detect - Clock Recovery)
All the registers must be reprogrammed after the voltage supply has been removed, otherwise they will be in the default state
25
1942C–WIRE–06/02
Reset Register (RESET)
Name
RESET
nbit
0
Writing in this register (0 or 1) triggers an asynchronous reset. This register can only be
written.
All registers return to reset state. The chip returns in power-down. So all the following
blocks are reset:
•
All registers to default value
•
Wake-up function.
•
Clock recovery function.
And with the power-down state, reset is applied to the following blocks:
•
Synthesizer dividers.
•
Clock recovery function.
•
PLL lock detect.
•
From powering up the supplies, it takes about 10 µs or at least 1.8V before the reset
state is established (Power-on Reset).
•
From reseting the device, one should wait about 10 µs before re-programming
•
RSSI detection block.
•
Discriminator clock (455 kHz).
Control Register (CTRL1)
Table 5. CTRL1 Overview
Name
PDN
RXTX
DATACLK
TXLOCK
PAPDN
WUEN
LNAGSEL
MVCC
TRSSI
HRSSI
nbit
31
30
29
28
27
26
25
24
23-18
17-15
init
0
0
0
1
0
0
0
0
(000000)2
(000)2
Name
TXLVL
TXFS
-
RXFS
XTALFQ
FSKBW
FSKPOL
DSREF
-
-
MOFFSET
-
nbit
14-12
11
10
9-8
7
6
5
4
3
2
1
0
init
(000)2
0
0
(10)2
0
1
1
1
0
0
0
0
Register reset value = (10000270)16
26
AT86RF211
1942C–WIRE–06/02
AT86RF211
Table 6. CTRL1 Detailed Description(1)(2)(4)(3)
Name
Number
of Bits
PDN
1
Comments
General power-down
0: power down mode; only the serial interface is active
1: AT86RF211 activated
reset value: 0
RXTX
1
Reception or transmission selection
0: Rx mode
1: Tx mode
reset value: 0
DATACLK
1
DATA clock recovery selection
0: no signal on DATACLK output pin
1: Clock recovery active: DATACLK activated
reset value: 0
TXLOCK
1
Transmission on PLL lock
0: transmission enabled, regardless of the PLL lock status
1: transmission only when the PLL is locked
reset value: 1
note: the PLL status is stored in the PLLL bit of the STATUS register
PAPDN
1
Power amplifier power down
0: Tx Power Amplifier power down mode
1: Tx Power Amplifier activated (only if PDN = 1)
reset value: 0
WUEN
1
Wake-up function enable
0: Wake-up function disabled, whatever the content of the wake-up control registers
1: Wake-up function activated, depending on the content of wake-up control registers
reset value: 0
LNAGSEL
1
LNA gain selection
0: maximum gain
1: minimum gain
reset value: 0
MVCC
1
RSSI or VCC power supply measurement selection
0: RSSI voltage measurement, value is stored in STAT register: MRSSI bits
1: VCC voltage measurement, value is stored in STAT register: MVCC bits
reset value: 0
TRSSI
6
RSSI value threshold
DATAMSG validated if RSSI ≥ TRSSI + HRSSI (high RSSI level)
DATAMSG inhibited if RSSI < TRSSI - HRSSI (low RSSI level)
reset value: (000000)2
HRSSI
3
Value RSSI hysteresis
reset value: (000)2
TXLVL
3
Tx PA output power selection
(000)2: minimum transmission level
(111)2: maximum transmission level
reset value: (000)2
TXFS
1
Tx frequency selection
0: F0 & F1
1: F2 & F3
reset value: 0
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1942C–WIRE–06/02
Table 6. CTRL1 Detailed Description(1)(2)(4)(3) (Continued)
Name
Number
of Bits
–
1
reserved, must be kept to reset value: 0
RXFS
2
RX frequency selection
(00)2: F0
(01)2: F1
Comments
(10)2: F2
(11)2: F3
reset value: (10)2
XTALFQ
1
Crystal frequency
0: 10.245 MHz (when IF1 = 10.7 MHz)
1: 20.945 MHz (when IF1 = 21.4 MHz)
reset value: 0
FSKBW
1
Discriminator range
0: Narrow Discriminator BW
1: Standard Discriminator BW
reset value: 1
FSKPOL
1
Polarity of DATAMSG
0: inverted signal
1: direct signal
reset value: 1
DSREF
1
Data Slicer reference voltage
0: external reference: SKFILT pin voltage
1: internal reference: DAC level voltage
reset value: 1
–
1
reserved, must be kept to reset value: 0
–
1
reserved, must be kept to reset value: 0
MOFFSET
1
0: internal ADC sets to VCC measurement
1: internal ADC sets to DISCOUT DC level measurement
reset value: 0
–
Notes:
1
reserved, must be kept to reset value: 0
1. The same ADC is used to measure RSSI or VCC voltage. When the VCC voltage is measured, the RSSI measurement is
stopped (previously measured RSSI is kept into STATUS Register). This can disturb the reception process (if a threshold is
used for DATAMSG validation). So, it is not recommended to measure VCC in reception mode.
2. VCC measurement can not be done when the AT86RF211 is in power-down mode.
3. While in VCC measurement, it is possible to measure the DC output of the discriminator.
4. Description of RSSI measurement with hysteresis mechanism: if the RSSI measurement is higher than the high RSSI level,
DATAMSG is validated (high RSSI level = TRSSI + HRSSI). If the RSSI measure is lower than the low RSSI level, DATAMSG is inhibited (low RSSI level = TRSSI - HRSSI). Between these two levels, DATAMSG validation depends on the
previous measurement.
Example:
TRSSI = 32 and HRSSI = 4 implies High RSSI level = 26 and Low RSSI level = 28
MRSSI sequence
27
32
35
36
35
32
29
28
27
25
RSSI level
NOK
NOK
NOK
OK
OK
OK
OK
OK
NOK
NOK
valid
valid
valid
valid
valid
DATAMSG
28
AT86RF211
1942C–WIRE–06/02
AT86RF211
Control Register (CTRL2)
Table 7. CTRL2 Overview
Name
DATARATE
DATATOL
LDCK
N0LD1
N1LD2
nbit
31-18
17-10
9
8-5
4-0
init
(0000)16
(00)16
0
(0010)2
(10111)2
Register reset value = (00000057)16
Table 8. CTRL2 Detailed Description
Name
Number of
bits
DATARATE
14
Comments
Received DATAMSG rate
This value must be programmed to have the DATACLK activated.
(selected with DATACLK bit in CTRL1 register).
Value from 1 kbps to 50 kbps
reset value: (0000)16
DATATOL
8
Tolerance for DATACLK, clock recovery
Recommended value = 2% of the rate.
reset value: (00)16
LDCK
1
Clock frequency is doubled to increase precision of PLL lock detection
0: 10 MHz clock frequency
1: doubled clock frequency
reset value: 0
N0LD2
4
PLL unlock condition trigger
Recommended values are reset values
reset value: (0010)2
N1LD2
5
PLL lock condition trigger
Recommended values are reset values
reset value: (10111)2
• Clock Recovery Function
The clock recovery function is activated by setting to ‘1’ the DATACLK bit of the CTRL1
register.
The clock recovery function provides on DATACLK pin the data clock, synchronized on
the received data flow. The targeted position for the rising edge of the clock is the middle of the data bit. It is then easy for the microcontroller to read without synchro troubles.
Clock recovery mechanism is based on the generation of a basic data clock with a
period given by DATARATE of CTRL2 with a step of about 100 ns. This basic clock is
synchronized on the received data flow with a phase correction step fixed by DATATOL
of CTRL2 register (step of about 100 ns also).
So, DATATOL can
–
compensate for the difference between the read data rates from transmitter
and receiver (fixed by DATARATE).
–
allow fast initial synchronization of data clock, avoiding bit transition times
and converge toward the middle of the bit.
–
keep the right data rate (no additional and no removed bit) when a noisy
data with bad bit transition position arrives.
The best value of DATATOL is a trade-off between these considerations. The typical
recommended value of RATETOL is 2% of DATARATE.
29
1942C–WIRE–06/02
If the tolerance is too high, the rate value is reached earlier, and the rate value could be
unstable (too big step).
If the tolerance is too low, it could be difficult to catch up the DATA and the function
could get lost.
Notice that maximum acceptable distance between two data transitions depends on the
precision of DATARATE versus transmitter actual data rate.
Synchronization mechanism is explained with the chronogram hereafter. The synchronization is done for the first bit. In worst case conditions, when data and clock arrive at the
same time, it begins at the second bit. Notice that the DATACLK signal is available as
soon as the DATACLK bit is programmed, whatever the state of DATAMSG pin.
The programmed data rate allows the creation of a basic clock at the programmed DATARATE frequency at the beginning of the reception. Then, the clock is shifted if
necessary from the tolerance value, depending on the previous DATA transition: the
clock is moved later or sooner, depending on the gap between CLOCK and DATA.
For example:
if DATARATE = 50 kbps, which is equivalent to a duration of 200 x T for 1 bit, with
T = 100 ns = base clock period.
if DATATOL = 2% x DATARATE = 4 x T.
Figure 34. Clock Recovery
DATAMSG
Tol = 4T
200T
Tol = 4T
DATACLK
Expected value
Synchronized values with DATAMSG
Expected value
• DATARATE Programming
This value must be programmed only when the DATA clock is needed on DATACLK
output pin of the chip.
The DATA rate can be programmed from 1 kbps to 64 kbps with 14 bits of CTRL2
register.
DATARATE is the period of the data rate and can be programmed with a resolution
given by the crystal oscillator period:
•
10.245 MHz oscillator, period = T = 97.6 ns
•
20.945 MHz oscillator, period = T = 95.5 ns
Some datarate values with the 10.245 MHz oscillator given for example:
30
DATARATE[13:0]
Rate
Period
(160)10
64 kbps
1 bit ~ 160 x T
(205)10
50 kbps
1 bit ~ 205 x T
(vv)10
……
1 bit ~ vv x T
(534)10
19.2 kbps
1 bit ~ 534 x T
(1024)10
10 kbps
1 bit ~ 1024 x T
AT86RF211
1942C–WIRE–06/02
AT86RF211
DATARATE[13:0]
Rate
Period
(1067)10
9.6 kbps
1 bit ~ 1067 x T
(2135)10
4.8 kbps
1 bit ~ 2135 x T
(4269)10
2.4 kbps
1 bit ~ 4269 x T
(10246)10
1 kbps
1 bit ~ 10246 x T
• Datatol Programming
The tolerance for the extraction of DATA rate must be nearly 2% of the RATE. The tolerance represents the step for the calculation of the rate.
If the tolerance is too high, rate value is reached earlier but the rate value could be
unstable (step too big).
If the tolerance is too low, it could be difficult to catch up the DATA and the clock recovery could get lost.
Some tolerance values given for example, with tolerance = 2% x DATARATE:
DATATOL[7:0]
Rate
Period
(3)10
64 kbps
1 bit ~ 3 x T
(4)10
50 kbps
1 bit ~ 4 x T
(vv)10
……
1 bit ~ vv x T
(20)10
10 kbps
1 bit ~ 20 x T
(21)10
9.6 kbps
1 bit ~ 21 x T
(43)10
4.8 kbps
1 bit ~ 43 x T
(85)10
2.4 kbps
1 bit ~ 85 x T
(205)10
1 kbps
1 bit ~ 205 x T
• PLL Lock Detect
The PLL lock function uses UP and DOWN signals from the internal phase detector.
These signals are analyzed synchronously with a clock frequency, depending of LDCK
bit programming (10 MHz or 20 MHz sampling).
LDCK is set to ‘1’ to double the clock frequency of the function PLL lock detect, to
increase the precision of the function.
N0LD2 triggers the unlock condition of the PLL.
N0LD2 = number of consecutive edges of the sampling clock with UP and DOWN active
before considering PLL unlocked.
This value must not be set to 0 or 1. The recommended value is default value, i.e. 2.
N1LD2 triggers the lock condition of the PLL.
N1LD2 = number of cycle at the PLL reference frequency, without any unlock condition
before considering PLL locked.
This value must not be set to 0.
It is recommended to use default values indicated in the table.
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1942C–WIRE–06/02
Frequency Registers
Table 9. Frequency Registers
Name
F0, F1, F2, F3
nbit
31-0
Name
Number
of bits
F0
32
Frequency code value F0
default register in TX mode ("0" code in FSK modulation).
F1
32
Frequency code value F1
default register in TX mode ("1" code frequency in FSK modulation).
F2
32
Frequency code value F2
default register in RX mode.
F3
32
Frequency code value F3
Note:
Comments
1. F0, F1, F2 and F3 registers must be programmed before using the device.
There is no simple relationship between frequency registers and the exact frequency. Atmel
provides a tool to program them on a production bench.
• Frequency Registers Selection
The FSK modulation is completely integrated. Two registers have to be programmed
(default F0 and F1) to allow "0" and "1" transmission.
The frequency register selection depends on the control register programming and on
the DATAMSG pin:
32
RXTX
RXFS
TXFS
DATAMSG
Mode
0
00
X
X
Receive LO is F0
0
01
X
X
Receive LO is F1
0
10
X
X
Receive LO is F2
0
11
X
X
Receive LO is F3
1
XX
0
0
Transmit "0" on F0
1
XX
0
1
Transmit "1" on F1
1
XX
1
0
Transmit "0" on F2
1
XX
1
1
Transmit "1" on F3
AT86RF211
1942C–WIRE–06/02
AT86RF211
In reception mode, only one frequency needs to be programmed. In transmission mode,
two different registers (F0 & F1), or (F2 & F3) must be programmed for “0” code and “1”
code transmission. The DATAMSG pin value actually selects the used register. The four
registers can also be set to define two channels, so that the AT86RF211 may switch
quickly from a channel to the other.
Mode
Programmed Frequency
RX
FCHANNEL ± IF1
TX
FCHANNEL ± deviation
Example:
FCHANNEL = 868.3 MHz
IF1 = 10.7 MHz
Deviation = ± 4 kHz
Mode
FSK
RX
868.3 ± 10.7 = 879 MHz or 857.6 MHz programmed in F2
TX
868.3 ± 0.004 = 868.304 MHz programmed in F1 when DATAMSG = “1”
and 868.296 MHz programmed in F0 when DATAMSG = “0”
Notes:
Status Register
1. In reception mode, one of the two frequencies (879 MHz or 857.6 MHz) can be chosen, taking into account external parameters (for example, the noise that brings the
image frequency).
2. Two frequencies are used to transmit data: 868.304 MHz for ”1” transmission and
868.296 MHz for ”0” transmission. The polarity of DATAMSG can be swapped using
bit 5 of CTRL1.
The STATUS register is used to read the status of internal functions (including the
wake-up function) or the output value of the internal ADC. This register can only be
read.
Table 10. Status Register Overview
Name
PLLL
MRSSI
MVCC
WAKEUP
-
MSGERR
nbit
30
29-24
23-18
17
16
15
Name
MSGDATL
MSGMRATE
nbit
14-10
9-0
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1942C–WIRE–06/02
Table 11. Status Register Detailed Description
Name
Number
of bits
PLLL
1
Comments
PLL Lock flag
0: PLL unlocked
1: PLL locked
reset value: 0
MRSSI
6
Measured RSSI level
reset value: (00)16
MVCC
6
Measured VCC power supply voltage or discriminator output when
MOFFSET = 1
reset value: (00)16
WAKEUP
1
WAKEUP flag
Copy of the WAKEUP pin, but not affected by polarity selection.
0: no wake-up message received
1: wake-up message received
reset value: 0
-
1
Reserved
reset value: 0
MSGERR
1
Wake-up message error in test message mode
0: no error detected in the received message
1: message received with error
reset value: 0
DTR Register
MSGDATL
5
Wake-up message data length
length of the data stored in WUD (received message).
reset value: 0
MSGMRATE
10
Wake-up message measured data rate
bit period extracted from message header of the wake-up
message.
Measured as a multiple of 1.56 µs (like RATE in WUR register).
0: 1 x 1.56 µs
(vv)10: vv x 1.56 µs
(3ff)16: 1024 x 1.56 µs
reset value: (000)16
The DTR register allows the user to precisely adjust the offset of the data slicer input.
Table 12. DTR Overview
Name
DSREF[3:0]
DISCHIGH
DISCLOW
nbit
5-2
1
0
init
(1000)2
0
0
Register reset value = (20)16
34
AT86RF211
1942C–WIRE–06/02
AT86RF211
Table 13. DTR Detailed Description
Name
Number
of bits
DSOFFSET
4
Comments
Data Slicer reference tuning
(0000)2 to (1111)2
reset value: (1000)2
DISCHIGH
1
Discriminator offset shift (high)
0: no shift
1: output level increased
reset value: 0
DISCLOW
1
Discriminator offset shift (low)
0: no shift
1: output level decreased
reset value: 0
Wake-up Control Register
Table 14. WUC Overview
Name
WUE
DATA
STOP
DATL
ADD
–
WPER
WL1
nbit
31
30
29
28-24
23
22
21-13
12-6
init
0
1
1
(11111)2
1
0
(001011111)2
(0000100)2
Name
WL2
ISTU
–
–
nbit
5-3
2
1
0
init
(010)2
0
0
0
Register reset value = (7f8be110)16
Table 15. WUC Detailed Description
Name
Number
of bits
WUE
1
Comments
Wake-up function enable
Returns to “0” when a valid message is received.
0: wake-up disable
1: wake-up enable
reset value: 0
DATA
1
Data content
0: message without data field
1: message with data field
reset value: 1
STOP
1
STOP field usage
0: fixed data length: data length set from 1 to 32 by DATL
1: variable data length: data length given by the STOP field location; DATL must be set to (11111)2
reset value: 1
35
1942C–WIRE–06/02
Table 15. WUC Detailed Description (Continued)
Name
Number
of bits
DATL
5
Comments
Data length
Valid in fixed data length mode (STOP = 0).
(00000)2: 1 bit (min data length value)
------------------(11110)2: 31 bits
(11111)2: 32 bits (max data length value)
reset value: (11111)2
ADD
1
Address content
0: message without address field
1: message with address field
reset value: 1
MSGTST
1
Message error test
0: no error detection mode
1: error detection enabling for debugging
reset value: 0
WPER
9
Wake-up period
Variable from 10 ms to 328 sec with an accuracy of ±20%.(on-chip RC oscillator)
reset value: 960 ms
reset value: (5f)16
WL1
7
Minimum delay before TEST1 (check of RSSI level)
Variable from 1ms to 1.024 sec
Delay calculation starts when the reference oscillator starts
reset value: 5 ms
reset value: (04)16
WL2
3
Minimum delay between TEST 1 and TEST 2 (check of header detection)
Variable as multiple of WL1 from 0 to 31 x WL1
reset value: 2 x WL1
reset value: (2)10
ISTU
1
Inhibit stuff mechanism
0: stuff is used for wake-up message
1: no stuff used in the wake-up message
reset value: 0
-
2
Reserved, must be kept to reset value
reset value: 0
• WPER Programming
WPER can be set from 10 ms to 328 sec with an accuracy of ±20%. A 10 ms period
clock is used for this period generation.
Bit 8 and 7 give a period multiplication factor of 1, 16 or 256 (with two serial by 16 clock
prescalers).
Bit 6 to 0 give the number of cycles of the divided clock from 1 to 128 (counter).
36
AT86RF211
1942C–WIRE–06/02
AT86RF211
Table 16. Wake Up Period Programming
WPER[8:0]
WPER[8:7]
WPER[6:0]
Period
Prescaler
Comments
(000)16
(00)2
(00)16
10 ms
1
1 x 10 ms
(001)16
(00)2
(01)16
20 ms
1
(1+1) x 10 ms
–
(00)10
(vv)10
–
1
(vv +1) x 10 ms
(07e)16
(00)2
(7e)16
1270 ms
1
1 x 1270 ms
(07f)16
(00)2
(7f)16
1280 ms
1
1 x 1280 ms
(101)16 or (081)16
(10)2 or (01)2
(01)16
170 ms
16
((16 x 1)+1) x 10 ms
(102)16 or (082)16
(10)2 or (01)2
(02)16
330 ms
16
((16 x 2)+1) x 10 ms
–
(10)2 or (01)2
(vv)10
–
16
((16 x vv)+1) x 10 ms
(17e)16 or (0fe)16
(10)2 or (01)2
(7e)16
20.2 sec
16
((16 x 126)+1) x 10 ms
(17f)16 or (0ff)16
(10)2 or (01)2
(7f)16
20.3 sec
16
((16 x 127)+1) x 10 ms
(181)16
(11)2
(01)16
2.57 sec
256
((256 x 1)+1) x 10 ms
(182)16
(11)2
(02)16
5.13 sec
256
((256 x 2)+1) x10 ms
–
(11)2
(vv)10
–
256
((256 x vv) +1) x 10 ms
(1fe)16
(11)2
(7e)16
323 sec
256
((256 x 126)+1) x 10 ms
(1ff)16
(11)2
(7f)16
325 sec
256
((256 x 127)+1) x 10 ms
• WL1 Programming
WL1 can be set from 1 ms to 1.024 sec . A 1 ms period clock is used for this delay
generation.
Bit 6 gives a period multiplication factor of 1 or 16 (by 16 clock prescaler).
Bits 5 to 0 give the number of cycles of the divided clock from 1 to 64 (counter).
Table 17. WL1 Programming
WL1[6:0]
WL1[6]
WL1[5:0]
Period
Prescaler
Comments
(00)16
0
(00)16
1 ms
1
1 x 1 ms
(01)16
0
(01)16
2 ms
1
(1+1) x 1 ms
(vv)10
0
(vv)10
vv + 1 ms
1
1x (vv +1) ms
(3e)16
0
(3e)16
63 ms
1
1 x 63 ms
(3f)16
0
(3f)16
64 ms
1
1 x 64 ms
(40)16
1
(00)16
16 ms
16
16 x 1 ms
(41)16
1
(01)16
32 ms
16
16 x 2 ms
–
1
(vv)10
–
16
16 x (vv +1) ms
(7e)16
1
(3e)16
1.008 sec
16
16 x 63 ms
(7f)16
1
(3f)16
1.024 sec
16
16 x 64 ms
37
1942C–WIRE–06/02
• WL2 programming
WL2 can be set as a multiple of WL1 from 0 to 31 WL1.
Table 18. WL2 Programming
WL2[2:0]
Period
Comments
(000)2
0
Simultaneous test of the RSSI and the header
(001)2
1 x WL1
(010)2
2 x WL1
(011)2
3 x WL1
(100)2
4 x WL1
(101)2
8 x WL1
(110)2
16 x WL1
(111)2
31 x WL1
Wake-up Data Rate Register
(WUR)
Table 19. WUR Overview
Name
WUOP
RATECHK
RATE
RATETOL
nbit
17-16
15
14-5
4-0
init
(01)2
0
(0000010000)2
(01000)2
Table 20. WUR Detailed Description
Name
Number of bits
WUOP
2
Comments
WAKEUP output polarity
(00)2: WAKEUP pin active low
(01)2: WAKEUP pin active high
(1x)2: WAKEUP pin open drain (active low, inactive tri-state)
reset value: (01)2
RATECHK
1
Data rate check
the data rate is automatically extracted from the HEADER field.
the data rate can be compared to RATE with a tolerance of plus or minus RATETOL.
Data rate is computed from a unit of 1.56 µs (Reference clock divided by 16).
0: data rate not checked.
1: data rate check done (header ignored if check fails).
reset value: 0
RATE
10
Data rate value
0d: min value = 1 x 1.56 µs
(1023)10: max value = 1024 x 1.56 µs
reset value: 64 x 1.56 µs
reset value: (63)10
RATETOL
5
Data rate tolerance
0d: min value = 0 x 1.56 µs
(31)10: max value = 31 x 1.56 µs
reset value: 8 x 1.56 µs
reset value: (8)10
38
AT86RF211
1942C–WIRE–06/02
AT86RF211
The data rate (in bps) and the decimal value to be coded in the register are related by
the equation:
640000
RATE = ------------------------rate (bps)
The following table gives the programming values of commonly used rates:
Rate
WUR RATE
1200 bits/sec
(533)10
2400 bits/sec
(267)10
4800 bits/sec
(133)10
9600 bits/sec
(67)10
Wake Up Address Register
(WUA)
Table 21. WUA Overview
Name
ADDL
ADD
nbit
24-20
19-0
init
(01001)2
(0f0f0)16
Table 22. WUA Detailed Description
Name
Number of bits
ADDL
5
Comments
Wake-up address length
0: wake-up address length = 1 bit
1: wake-up address length = 2 bits
..........
(19)10: wake-up address length = 20 bits
>(19)10: forbidden
reset value: 10 bits
ADD
20
Wake-up address
If wake-up address length is less than 20 bits, MSB bits are ignored
reset value: (0f0f0)16
Concerning this register, attention should be paid to the fact that the last bit of the
address field is not taken into account when testing the address field that is received.
Thus the last bit must be programmed and counted in the address length but it can be
either "0" or "1".
39
1942C–WIRE–06/02
Wake-up Data Register (WUD)
Table 23. WUD Overview
Name
WUD
nbit
(data length -1) - 0
Table 24. WUD Detailed Description
Name
Number of bits
WUD
Length
Note:
40
Comments
Wake-up message data
Warning: The length of this register is variable:
* case fixed data length (STOP = 0 of WUC) data length is given by DATL of WUC.
* case variable data length (STOP = 1 of WUC) data length is given by MSGDATL of STAT register.
Warning: The first bit of received data is the LSB: WUD[0].
To use this mode, please refer to the corresponding application note.
AT86RF211
1942C–WIRE–06/02
AT86RF211
Electrical
Specification
ESD sensitive device: storage or handling of the device must be carried out
according to usual protection rules.
Absolute Maximum
Ratings
Temperature
+95°C
Storage temperature
-65 to +150°C
Supply voltage
0 to 3.95V
Digital input voltage
-0.3 to VCC + 0.3V
RXIN input power
0 dBm
Note:
DC Characteristics
Stresses beyond the conditions listed above may cause permanent damage to the
device. Exposure to Absolute Maximum Ratings conditions for an extended period may
affect device reliability.
Unless otherwise specified, data is given for T = 25°C, VSUPPLY = 2.7V
Parameter
Min
Supply voltage
2.4
Typ
Max
Unit
3.75
V
Comment
(1)
Supply current
0.5
µA
Power-down
Supply current
3
µA
Sleep mode
Supply current
29
mA
Rx mode
Supply current
35
mA
Tx mode, Pout = +10 dBm at 433 MHz
Supply current
20
mA
Tx mode, PDN-PA on
Operating temperature
Note:
-40
+85
°C
1. The allowed supply voltage of the AT86RF211 is higher than 3.75V. However, we
strongly recommend not to exceed 3.75V from now on, to be compliant with future
versions of the device.
41
1942C–WIRE–06/02
Digital CMOS DC
Characteristics
Unless otherwise specified, data is given for T = 25°C, VSUPPLY = 2.7V
Name
Parameter
Vil
CMOS low level input voltage
- Normal input(2)
- Schmitt trigger input(3)
Vih
CMOS high level input voltage
- Normal input(2)
- Schmitt trigger input(3)
(1)
Voh
Min
Typ
Max
Units
0.3*Vcc
0.2*Vcc
V
V
0.7*Vcc
0.85*Vcc
CMOS low level output voltage(1)
Vol
Note:
Conditions
CMOS high level output voltage
V
V
Iol = 1 mA
Ioh = - 1 mA
0.2*Vcc
0.8*Vcc
V
V
1. For digital CMOS pins : SDATA, DATAMSG, DATACLK, WAKEUP.
2. For digital CMOS pins: SLE, SCK, SDATA
3. For digital CMOS pins: DATAMSG
• Timings
Name
Parameter
Conditions
tr = tf
CMOS rise/fall times
CL = 50 pF ; 20% to 80%
F
SCK frequency
0
T
SCK period
200
ns
tw
SCK low or high time
60
ns
tsd
SDATA setup before SCK rising
40
ns
thd
SDATA hold after SCK rising
40
ns
tpd
SDATA output propagation delay after SCK falling
(read mode) (CL = 30 pF)
2
50
ns
tpzon
Delay to switch SDATA to output after SCK falling
(read mode)
3
50
ns
tdle
Minimum delay between an edge of SLE and an
edge of SCK
40
tpzd
Delay to switch SDATA to input (tri-state) after SLE
rising (read mode)
40
ns
Max load for CMOS output pins
50
pF
CL(1)
Note:
42
Min
Typ
Max
Units
30
ns
5
MHz
ns
These timings refer to the Figure 33 on page 25.
AT86RF211
1942C–WIRE–06/02
AT86RF211
Synthesizer
Specification
Unless otherwise specified, data is given for T = 25°C, VSUPPLY = 2.7V
ii
Parameter
Min
Frequency Range
Max
Unit
Comments
400
480
MHz
Digital programming
Frequency Range
800
950
MHz
Digital programming
Crystal Frequency
10.235
10.245
10.255
MHz
IF 1 = 10.7 MHz(1)
Crystal Frequency
20.925
20.945
20.965
MHz
IF 1 = 21.4 MHz(1)
5
8
ms
Depending on crystal
specifications
Lock Time(2)
300
µs
From oscillator settling
Lock Time(2)
30
µs
100 kHz shift
Phase Noise 400 to 480 MHz
-80
dBc/Hz
At 10 kHz from the carrier
Phase Noise 800 to 950 MHz
-75
dBc/Hz
At 10 kHz from the carrier
Phase Noise 400 to 480 MHz
-91
dBc/Hz
At 100 kHz from the carrier
Phase Noise 800 to 950 MHz
-86
dBc/Hz
At 100 kHz from the carrier
Oscillator Settling Time
Notes:
Typ
1. Crystal frequency can be slightly changed but since IF2 = IF1 - Crystal frequency, IF2 will shift and must remain within the
IF2 filter and discriminator bandwidth.
2. With the "typical implementation" loop filter.
Receiver Specification
Parameter
Unless otherwise specified, data is given for T = 25°C VSUPPLY = 2.7V
Min
Typ
Max
Unit
Comments
21.4 MHz also possible
IF1
10.7
MHz
IF1 Filter Impedance
330
Ω
IF2
455
kHz
IF2 Filter Impedance
1700
Ω
FSK Sensitivity
-105
dBm
Noise Figure
15
dB
Input IP3
-15
dBm
Typical performance with a BER of 1% at input pin
RXIN (45). BW = ± 10 kHz, ∆F = ± 7.5 kHz; Brate =
4800 bps(1)
Input matched, complete RX chain
Max Input Power
-5
dBm
BER < 10%
Note:
1. The overall sensitivity depends on measurements conditions and external components, i.e.:
-100 dBm for BW = ± 10 kHz, ∆F = ± 7.5 kHz, Brate = 4800 bps with RF switch used and external SAW filter
43
1942C–WIRE–06/02
Transmitter Specification Unless otherwise specified, data is given for T = 25°C, VSUPPLY = 2.7V,
RPOWER = 18 kΩ.
Parameter
Min
Typ
Output Power
+10
Output Power
Output Power
Unit
Comments
+14
dBm
433 MHz band(1)
+10
+12
dBm
868 MHz band(1)
+8
+10
dBm
915 MHz band(1)
Output Power Dynamic Range
12
dB
Digital programming(2)
Automatic Level Control Accuracy
1
dB
Constant conditions
Automatic Level Control Accuracy
±2
dB
Against VCC, T°(3)
FSK Data Rate
RX to TX Toggle Time
Notes:
44
Max
64
200
kbps
µs
Typical loop filter implementation
1. Output power for Rpower = 10 kΩ and TXLVL = "111"
2. The maximum power is set by an external resistor, connected to pin RPOWER. The output power can be digitally programmed/re-programmed, up to -12 dB below this limit, by means of a 3-bit word: TXLVL of CTRL1 register.
3. The output power is regulated against process, temperature and power supply variations by an internal ALC loop.
AT86RF211
1942C–WIRE–06/02
AT86RF211
Typical Application
Implementation
Optional
SAW Filter
VCC
VCC
SAW
VCC
VCC
VCC
IF1 Filter: 10.7 MHz
or
21.4 MHz
Rpower
ANTENNA
IF2
Optional
Ceramic
Filter
(455 kHz)
AT86RF211
VCC
Optional
RC Filter
VCC
10.245 MHz
or
20.945 MHz
Note:
Accurate information about parts and values of components to be used around AT86RF211 are described in our application
notes. "RF Bill-of-Material/cost for 868-915 MHz applications".
45
1942C–WIRE–06/02
Layout
Reference Design Top Layer
Each unused area must be filled
with copper and connected to the
bottom side ground plane
Decoupling capacitors remain
close to the supply pins
Reference Design Bottom
Layer
One-block ground plane
with no slot under the
whole RF area
This small slot is allowed
as it is under the RF211: thus
there is no track above
46
AT86RF211
1942C–WIRE–06/02
AT86RF211
Packaging
Information
48 lead TQFP
Dimension
Nominal Value (mm)
Tolerance
Dimension
Nominal Value (inch)
Tolerance
A
1.60
max
A
0.063
max
A1
0.05 min/0.15 max
A1
0.002 min/0.06 max
A2
1.40
±0.05
A2
0.055
±0.002
D
9.00
±0.20
D
0.354
±0.008
D1
7.00
±0.10
D1
0.275
±0.004
E
9.00
±0.20
E
0.354
±0.008
E1
7.00
±0.10
E1
0.275
±0.004
L
0.60
+0.15/-0.10
L
0.024
+0.006/-0.004
e
0.50
basic
e
0.020
basic
b
0.22
±0.05
b
0.009
±0.002
ccc
0.1
max
ccc
0.004
max
Ordering information
Full Part Number
Package
Conditionning
AT86RF211 DAI
TQFP48
Tray
AT86RF211 DAI-R
TQFP48
Tape & reel
47
1942C–WIRE–06/02
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© Atmel Corporation 2002.
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Printed on recycled paper.
1942C–WIRE–06/02
0M